/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraSystemInstance.h
Manually advances this system's simulation by the specified number of ticks and tick delta. To be advanced in this way a system must be in solo mode or moved into solo mode which will add additional overhead.
void AdvanceSimulation ( int32 TickCountToSimulate, float TickDeltaSeconds )